1. Field of the Invention
The present invention relates to a pipe coupling including a female coupler and a male coupler that are connected to one another.
2. Description of the Related Art
A female coupler and a male coupler, which together constitute a pipe coupling, may be provided in their respective fluid passages with a valve to enable opening or closing of the passages. These valves are supported in the respective passages by using valve support members. The valve support members are prepared separately from the female coupler body and the male coupler body and, during assembly, they are fitted into the female coupler body and the male coupler body, respectively (for example, see Japanese Utility Model Application Post-Examination Publication Nos. Sho 50-39862, Sho 55-120885 and Sho 54-99116).
In conventional female and male couplers, however, preparation and fitting of valve support members requires complicated operations to be carried out. Moreover, it is necessary to configure the valve support members such that they can be securely fitted into respective fluid passages in the female coupler and the male coupler. Therefore, a problem arises in the conventional female and male couplers that a cross-sectional area of their respective fluid passages is caused to become narrow, resulting in an increase in resistance therein.
In view of the problem described above, a female coupler and a male coupler have been disclosed in which valve support members are integrally formed on passage wall surfaces that define fluid passages in the female coupler and the male coupler (for example, see Japanese Patent Application Unexamined Publication (KPKAI) No. Hei 4-73488).
However, production of this type of male and female coupler is complicated and is therefore impractical.
There has also been disclosed a female coupler and male coupler in which a female coupler, for example, includes a cylindrical female coupler body having a front end opening for connection with a male coupler, wherein a cylindrical pipe connection adapter is coaxially inserted into the female coupler body from a rear end opening thereof and connected to the female coupler body. The front end of the pipe connection adapter is closed, and a hole is provided in the center of the closed end. A valve guide rod extending rearward from a valve element positioned forward of the closed end is passed through the center hole to support the valve element. In addition, the side wall of the pipe connection adapter is provided with an opening for passing a fluid (for example, see Japanese Utility Model Application Post-Examination Publication No. Sho 57-40399).
Since it is not necessary to separately provide the above-described female coupler with a valve support member, assembly of the coupler is facilitated. However, because a fluid must be able to pass through a passage around the front end of the cylindrical pipe connection adapter, the cross-sectional area of the through-hole in the female coupler body that receives the adapter has to be increased at a portion around the front end of the adaptor. It is also necessary to provide at the distal end of the through-hole a valve seat having a small diameter, which makes it difficult to form the hole in the female coupler body.